High-voltage generator with multi-stage selection in low-voltage transistor process

ABSTRACT

The present disclosure relates to a high-voltage generator with multi-stage selection in low-voltage transistor process which include a boosted circuit, a plurality of switch and a feedback circuit. The boosted circuit includes multiple charge pump, so that can generate a DC output voltage higher or lower than the input signal. Turning on or turning off each switch controlled by a control signal respectively. Both ends of the circuit is connected to the output end of the high-voltage generator and charge pumps. By controlling the turning on or turning off each switch, it determines the magnitude of the boost and it also can ensure that switches will not be damaged due to excessive voltage difference.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Taiwan Application Serial Number106141216, filed Nov. 27, 2017, which is herein incorporated byreference in its entirety.

BACKGROUND Technical Field

The present disclosure relates to a high-voltage generator withmulti-stage selection in low-voltage transistor process. Moreparticularly, it can boost an input signal through multiple charge pump.

Description of Related Art

In recent years, with the development of biomedical electronictechnology, many new stimulator circuits have been designed fordiagnosis, rehabilitation or prevention of disease generation anddeterioration. The stimulator circuit is used to give electricalstimulation to the biological tissue. Since the impedance of biologicaltissue is too large, the stimulator circuit chip, which is used in thefield of biomedicine, must be configured a “high-voltage generator” soas to allow the stimulator circuit operate normally and exert theexpected effect.

In addition, since the impedance of biological tissue will be differentwith the application of the different ways, the high-voltage generatorwithin the stimulator circuit must be able to vary with the impedance ofbiological tissue and provide an output voltage range between severalvolts and tens of volts so as to meet the needs of the application.

However, in practice, the stimulator circuit chip is often embedded inthe organism, so the volume and area will be one of the key points inthe design. Thus, how to reduce the size and the area of a stimulatorcircuit chip under the premise of ensuring the performance anddurability of the stimulator circuit is an important target in theindustry, and this is also the subject of the present disclosure to bediscussed herein.

SUMMARY

One aspect of the present disclosure is a high-voltage generator withmulti-stage selection in low-voltage transistor process. Thehigh-voltage generator comprises a boost circuit, at least a first stageswitch and a second stage switch and a feedback circuit. The boostcircuit comprises at least a first stage charge pump and a second stagecharge pump in series. An input end of the first stage charge pump iselectrically coupled to an input end of the high-voltage generator. Aninput end of the second stage charge pump is electrically coupled to anoutput end of the first stage charge pump. An output end of the secondstage charge pump is electrically coupled to an output end of thehigh-voltage generator. The first stage switch and the second stageswitch are respectively connected in parallel with the first stagecharge pump and the second stage charge pump, and each switch comprisesat least one low-voltage transistor. The feedback circuit electricallyis coupled to the output end of the high-voltage generator through afirst end of the feedback circuit and electrically coupled to the chargepumps through a plurality of clock signal providing ends of the feedbackcircuit. When both of the first stage switch and the second stage switchare turned off, the high-voltage generator receives an input signalthrough the input end of the high-voltage, and boosts the input signalthrough the first stage charge pump and the second stage charge pump,sequentially. When the first stage switch is turned on and the secondstage switch is turned off, the high-voltage generator boosts the inputsignal through the second stage charge pump. Voltages across the ends ofthe first stage switch and voltages across the ends of the second stageswitch are not exceed one boost voltage difference.

It is to be understood that both the foregoing general description andthe following detailed description are by examples, and are intended toprovide further explanation of the disclosure as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be more fully understood by reading thefollowing detailed description of the embodiment, with reference made tothe accompanying drawings as follows:

FIG. 1 is a schematic diagram of an improved high-voltage generatorcircuit.

FIG. 2 is a schematic diagram of a high-voltage generator withmulti-stage selection in low-voltage transistor process of the presentdisclosure.

FIG. 3 is a partial circuit diagram of the high-voltage generator of thepresent disclosure.

FIG. 4 is a schematic diagram of a SPDT switch of the presentdisclosure.

FIG. 5 is a schematic circuit diagram of a front SPDT switch of thepresent disclosure.

FIG. 6 is a schematic circuit diagram of a back SPDT switch of thepresent disclosure.

DETAILED DESCRIPTION

For the embodiment below is described in detail with the accompanyingdrawings, embodiments are not provided to limit the scope of the presentdisclosure. Moreover, the operation of the described structure is notfor limiting the order of implementation. Any device with equivalentfunctions that is produced from a structure formed by a recombination ofelements is all covered by the scope of the present disclosure. Drawingsare for the purpose of illustration only, and not plotted in accordancewith the original size.

It will be understood that when an element is referred to as being“connected to” or “coupled to”, it can be directly connected or coupledto the other element or intervening elements may be present. Incontrast, when an element to another element is referred to as being“directly connected” or “directly coupled,” there are no interveningelements present. As used herein, the term “and/or” includes anassociated listed items or any and all combinations of more.

In the course of the research, the inventor found that the currenthigh-voltage generator circuit chips can not completely balanceperformance, durability and volume. In order to flexibly generate avoltage of several volts to several tens of volts, there is aconventional method to change the pumping frequency of the charge pumpin the high-voltage generator circuit and to stabilize the voltagepassing through the feedback circuit. But this method is too lowefficiency and lack of practicality.

In recent years, there is another high-voltage generator circuit, whichis equipped with a multi-stage and independent boost circuits. Accordingto the output voltage requirements, the high-voltage generator circuitwill use the corresponding boost circuit. For example, when the inputvoltage needs to be doubled, a boost circuit with a single charge pumpis driven. When the input voltage needs to be tripled, a boost circuitwith two charge pumps in series is driven. Although this method caneffectively ensure the conversion efficiency, it still will increase thevolume so it is not a complete solution.

FIG. 1 is another improved high-voltage generator circuit 1. Thehigh-voltage generator circuit 1 includes a booster circuit 11 and afeedback circuit 12. The booster circuit 11 includes multiple chargepumps 111-114 and multiple switches 115-117. The feedback circuit 12includes a differential amplifier 121 and an oscillator 122, and canreceive control signals E1-E3 to control the charge pumps 111-114 andthe switches 115-117.

For example, when the high-voltage generator circuit 1 needs to boostthe signal double, the switches 115-117 are turned on so that the signalreceived by the input end V1 passes through the switches 115-117 withoutboost by the charge pumps 111-113. The high-voltage generator circuit 1boosts the signal only by the charge pump 114. Similarly, when thehigh-voltage generator circuit 1 need to boost signal four times, itonly needs to turn off all the switches 115-117, the four charge pumps111-114 can be used to complete the voltage boost four times, and theboosted voltage is output from the output end V2.

However, the inventor found that the high-voltage generator shown inFIG. 1 has a great disadvantage in practical use. Use the operation modeof “boost signals four times” as an example, when the voltage of theinput end V1 is VA, and the switches 115-117 are all turned off, thenode between the charge pump 113 and the charge pump 114 will have fourtimes the VA voltage (boosted three times). At this time, the switch 117is not turned on, but the voltages across the ends of the switch 117 arethree times VA (VA and four times of VA). This excessive voltagedifference will easily cause damage to the switch 117.

The high-voltage generator shown in FIG. 1 can solve the problem ofdurability through using a “high-voltage process” to manufacture theswitches 115-117. However, in the application of biomedical chips (forexample, implanted chips for the suppression of epilepsy), in additionto the high-voltage generator, there are many components such asrectifiers, receivers, drivers and biological signal processors. Ifusing a separate process to produce the high-voltage generator circuit,it is bound to unable to ensure that the biomedical chip is lightweight.On the other hand, If all components are made of high-pressure process,the volume can be saved, but will increase production costs. Thus, thehigh-voltage generator shown in FIG. 1 unable to balance multiple designrequirements, such as efficiency, durability and volume.

In order to solve the aforementioned problems, the inventor designed ahigh-voltage generator of the present disclosure. FIG. 2 shows aschematic diagram of a high-voltage generator with multi-stage selectionin low-voltage transistor process in some embodiments of the presentdisclosure. The high-voltage generator 2 is applied to a biomedical chip(as above, such as the implanted chips for the suppression of epilepsy),but not limited thereto.

The high-voltage generator 2 includes a boost circuit 20, at least afirst stage switch 21, at least a second stage switch 22 and a feedbackcircuit 23. The boost circuit 20 is consists of at least a first stagecharge pump 201 and a second stage charge pump 202 in series. However,the boost circuit 20 may also be increased in number according to designrequirements. The input end of the first stage charge pump 201 iselectrically coupled to the input end V_(in) of the high-voltagegenerator 2. The input end of the second stage charge pump 202 iselectrically coupled to the output end of the first stage charge pump201. The output end of the second stage charge pump 202 is directly orindirectly electrically coupled to the output end V_(out) of thehigh-voltage generator 2.

The first stage switch 21 is connected in parallel with the first stagecharge pump 201. The second stage switch 22 is connected in parallelwith the second stage charge pump 202. Each of the switches 21,22 isconsists of at least one low-voltage transistor, and the detailedstructure will be described later. However, the present disclosure isnot limited to the structure of the switches. The switches 21, 22 canrespectively receive the control signals D1 and D2 from the stimulatorcircuit chip (such as a driver in the chip) to determine the status ofthe switches D1 and D2.

A first end of the feedback circuit 23 is electrically coupled to theoutput end V_(out) of the high-voltage generator 2. A plurality of clocksignal providing ends of the feedback circuit 23 are electricallycoupled to the charge pumps 201 and 202 respectively for providing aclock signal to each charge pumps 201, 202. For example, when thevoltage at the output end V_(out) of the high-voltage generator 2 is toolow, the feedback circuit 23 can raise the frequency of the clock signalto speed up the operation frequency of the charge pump 201, 202 toeffectively maintain the output end V_(out) at high voltage. On theother hand, when the voltage at the output end V_(out) of thehigh-voltage generator 2 is excessively high, the feedback circuit 23can lower the frequency of the clock signal and slow down the operatingfrequency of the charge pump 201, 202 to effectively control the outputend V_(out) to the relatively low voltage, and then to stabilize theoutput voltage within an expected range. Refer to FIG. 2, each of theswitches 21 and 22 can be turned on or off by the control signals D1 andD2, respectively. According to the switches 21, 22 are turned on or off,it is determined whether the charge pumps 201 and 202 boost the signalof the input V_(in).

When both the first stage switch 21 and the second stage switch 22 areturned off, an input signal, which is received at the input end V_(in)of the high-voltage generator 2, is sequentially transmitted through thefirst stage charge pump 201 and the second stage charge pump 202 toboost double. On the other hand, when the first stage switch 21 isturned on and the second stage switch 22 is turned off, the input signalV_(in) is boosted only once by the second stage charge pump 202. At thistime, the voltages across the first stage switch 21 are zero, and thevoltages across the ends of the second stage switch 22 have only oneboost voltage difference (that is, V_(in)). As mentioned above, eachcharge pump 201, 202 can adjust the frequency of operation according tothe frequency of the received clock signal to ensure the overalloperation efficiency of the high-voltage generator 2.

In the present disclosure, two ends of each of the switches 21 and 22are respectively connected to the two ends of the corresponding chargepump 201 and 202 through connecting switches 21 and 22 in parallel toeach of the charge pumps 201 and 202 respectively. In this way, nomatter whether the switches 21 and 22 are turned on or turn off, thereis only one boost voltage difference across of two ends of the switches21 and 22, which will not damage the switches 21 and 22. Accordingly,the high-voltage generator 2 and other components can be integrated intoa single chip by using a low-voltage process, and while ensuring theefficiency and durability, effectively control the production cost andthe chip volume.

The structure of each of the switches 21 and 22 will be furtherdescribed below. Please refer to FIG. 2-FIG. 4, wherein the high-voltagegenerator 2 in FIG. 3 omits the feedback circuit 23 so that to highlightthe switches 21 and 22. The first stage switch 21 includes a first frontsingle pole double throw (SPDT) switch 31, a first inverter 32, a firstback single pole double throw (SPDT) switch 33 and a first transistorswitch 34. In this embodiment, the internal circuit structures of thefirst front SPDT switch 31 and the first back SPDT switch 33 are thesame. FIG. 4 shows a schematic diagram of SPDT switch, which includes acontrol end 51 and two switch ends 52,53 and a reaction end 54. However,the positions of the “reaction end 54” of the first front SPDT switch 31and the first back SPDT switch 33 are different and will be described indetail later.

The control end of the first front SPDT switch 31 is configured toreceive a control signal D1. The two switch ends of the first front SPDTswitch 31 are respectively electrically coupled to the input end of thefirst stage charge pump 201 and a ground terminal GND. The input end ofthe first inverter 32 is electrically coupled to the reaction end of thefirst front SPDT switch 31. The control end of the first back SPDTswitch 33 is also configured to receive the control signal D1. Twoswitch ends of the first back SPDT switch 33 are electrically coupled tothe output end of the first stage charge pump 201 and the output end ofthe first inverter 32.

The first transistor switch 34 is consists of at least one low-voltagetransistor. Two ends of the first transistor switch 34 are respectivelyconnected in parallel with the first stage charge pump 201, and thecontrol end of the first transistor switch 34 is electrically coupled tothe reaction end of the first back SPDT switch 33.

The second stage switch 22 also includes a second front SPDT switch 41,a second inverter 42, a second back SPDT switch 43, and a secondtransistor switch 44. The control end of the second front SPDT switch 41is configured to receive another control signal D2. The second switchend of the second front SPDT switch 41 is electrically coupled to theinput end of the second stage charge pump 202 and the output end of thefirst inverter 32.

The input end of the second inverter 42 is electrically coupled to thereaction end of the second front SPDT switch 41. The control end of thesecond back SPDT switch 43 is configured to receive the other controlsignal D2. Two switch ends of the second back SPDT switch 43 arerespectively electrically coupled to the output end of the second stagecharge pump 202 and the output end of the second inverter 42. The secondtransistor switch 44 is consists of at least one low-voltage transistor.Two ends of the second transistor switch 44 are connected in parallelwith the second stage charge pump 202, and a control end of the secondtransistor switch 44 is electrically coupled to the reaction end of thesecond back SPDT switch 43.

Similarly, the internal circuits of the second front SPDT switch 41 andthe second back SPDT switch 43 have the same structure. As shown in FIG.4, the SPDT switch includes a control end 51, two switch ends 52, 53 anda reaction end 54. However, the positions of the “reaction end 54” ofthe first front SPDT switch 31 and the first back SPDT switch 33 aredifferent, and the difference will be described in detail later.

To facilitate understanding the operation mode of the high-voltagegenerator of the present disclosure, the operation mode of the switches21, 22 will be described below: Refer to FIG. 3, when the control signalD1 generates a rising from a low voltage to a high voltage, the reactionend 54 conducts to the switch end 52 and connect to the input end V_(in)of the high-voltage generator 2 (here define the voltage magnitude ofthe input V_(in) as V_(DD)) according to the characteristics of the SPDTswitch (see FIG. 4). At this time, the NMOS transistor in the firstinverter 32 is turned on and the PMOS transistor is turned off, so thatthe output end of the first inverter 32 is maintained to the groundsignal.

Since the control end of the first back SPDT transistor 33 is configuredto receive the same control signal D1, therefore, the reaction end isconnected to the output end of the first inverter 32, that is, remainsat ground, so that the first transistor switch 34 is turned on. Thevoltage signal at the input end will be bypassed through the firsttransistor switch 34 without passing through the first stage charge pump201. That is, the output voltage of the first stage charge pump 201remains at V_(DD).

Similarly, if the control signal D2 is falling from a high voltage to alow voltage, according to the characteristics of the SPDT switch, thereaction end will be connected to the switch end corresponding to theoutput end of the first inverter 32 and is maintained to the groundsignal. At this time, the NMOS of the second inverter 42 is turned offand the PMOS is turned on so that the voltage at the output end of thesecond inverter 42 approaches V_(DD).

Since the control end of the second back SPDT switch 43 is alsoconfigured to receive the same control signal D2, the reaction end ofthe second back SPDT switch 43 is connected to the switch endcorresponding to the output end of the second stage charge pump 202. Thesecond transistor switch 44 is turned off so as to the voltage V_(DD) atthe output end of the first stage charge pump 201 is boosted to 2V_(DD)through the second stage charge pump 202.

In the foregoing embodiment, the first transistor switch 34 and thesecond transistor switch 44 are PMOS transistors. In addition, FIG. 2and FIG. 3 show a high-voltage generator with two charge pumps, but itmay increase the number of charge pumps and switches to achieve morelevels of boost function.

In addition, the structure of the front SPDT switch (i.e. correspondingto the first front SPDT switch 31 and the second front SPDT switch 41)in the present disclosure is further described. Referring to FIG. 5, thefront SPDT switch includes a first coupling capacitor 61, a secondcoupling capacitor 62, a first cross-coupled transistor 63, and a secondcross-coupled transistor 64. One end of the first coupling capacitor 61is electrically coupled to the control end 51 of the front SPDT switchthrough an inverter 610. One end of the second coupling capacitor 62 iselectrically coupled to the control end 51 of the front SPDT switch, andthe other end of the second coupling capacitor 62 is electricallycoupled to the reaction end 54.

The first cross-coupled transistor 63 is electrically coupled to thefirst coupling capacitor 61, the second coupling capacitor 62, and aswitch end 52 of the front SPDT switch 5. The second cross-coupledtransistor 64 is electrically coupled to the first coupling capacitor61, the second coupling capacitor 62 and the other switch end 53 of theSPDT switch 5. The signal phases of the control end 51 and the reactionend 54 are in phase.

When the control end 51 changes from a low voltage to a high voltage,the voltage of the reaction end 54 changes according to the followingformula:

${{\Delta\; V} = \frac{C_{q} \cdot V_{DD}}{C_{q} + C_{par}}},$

Wherein C_(q) is the capacitor of the second coupling capacitor 62,C_(par) is the parasitic capacitor of the reaction end 54, and V_(DD) isthe voltages across the two switch ends 52, 53. In this embodiment, thefirst cross-coupled transistor 63 uses a pair of NMOS transistors andthe second cross-coupled transistor 64 uses a pair of PMOS transistors.In addition, the second cross-coupled transistor 64 is respectivelyconnected with two bypass circuits 65 in parallel, and each of thebypass circuits 65 is consists of multiple diodes in series. When thevoltage at the switch end 53 instantaneously falls, the instantaneousvoltage variation bypass through the bypass circuit 65 to prevent thesecond cross-coupled transistor 64, the transistors in any of the chargepumps 201 and 202, and the switches 21 and 22 got damaged.

Similarly, refer to FIG. 6. FIG. 6 is a circuit diagram of the back SPDTswitch (i.e. the first back SPDT transistor 33 and the second back SPDTswitch 43). The back SPDT switch includes a first coupling capacitor 61,a second coupling capacitor 62, a first cross-coupled transistor 63 anda second cross-coupled transistor 64. One end of the first couplingcapacitor 61 is electrically coupled to the control end 51 of the backSPDT through an inverter 610, and the other end of the first couplingcapacitor 61 is coupled to the reaction end 54. One end of the secondcoupling capacitor 62 is electrically coupled to the control end 51 ofthe front SPDT switch 5.

The first cross-coupled transistor 63 is electrically coupled to thefirst coupling capacitor 61, the second coupling capacitor 62 and theswitch end 52 of the front SPDT switch 5. The second cross-coupledtransistor 64 is electrically coupled to the first coupling capacitor61, the second coupling capacitor 62 and another switch end 53 of theSPDT switch 5. The signal phase of the control end 51 and the reactionend 54 is out of phase, and is slightly different from the front SPDTswitch.

Comparing FIG. 5 and FIG. 6, the difference between the front SPDTswitch and the back SPDT switch is that the reaction end 54 of each ofthe front SPDT switch is electrically coupled to the other end of thesecond coupling capacitor 62. The reaction end 54 of each of the backSPDT switch is electrically coupled to the other end of the firstcoupling capacitor 61, so that there is a phase difference between thesignals at the reaction ends 54.

Referring to FIG. 2, in the present embodiment, the feedback circuit 23includes a differential amplifier 231, a voltage-controlled oscillator232 and a clock circuit 233. The input end of the differential amplifier231 is electrically coupled to the output end V_(out) of thehigh-voltage generator 2 and a reference voltage VR. The input end ofthe voltage-controlled oscillator 232 is electrically coupled to theoutput end of the differential amplifier 231. An input end of the clockcircuit 233 is electrically coupled to an output end of thevoltage-controlled oscillator 232. An output end of the clock circuit233 is coupled to each of the charge pumps 201 and 202. The clockcircuit 233 is configured to receive the input V_(in) and output a clocksignal with a corresponding frequency to the charge pump 201, 202through the feedback signal of the voltage-controlled oscillator 232 soas to adjust the operating frequency of each charge pump 201 and 202.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentdisclosure without departing from the scope or spirit of the presentdisclosure. In view of the foregoing, it is intended that the presentdisclosure cover modifications and variations of this present disclosureprovided they fall within the scope of the following claims.

What is claimed is:
 1. A high-voltage generator with multi-stageselection in low-voltage transistor process, comprising: a boost circuitcomprising at least a first stage charge pump and a second stage chargepump in series, wherein an input end of the first stage charge pump iselectrically coupled to an input end of the high-voltage generator, aninput end of the second stage charge pump is electrically coupled to anoutput end of the first stage charge pump, an output end of the secondstage charge pump is electrically coupled to an output end of thehigh-voltage generator; at least a first stage switch and a second stageswitch, wherein the first stage switch and the second stage switch arerespectively connected in parallel with the first stage charge pump andthe second stage charge pump, and each switch comprises at least onelow-voltage transistor; and a feedback circuit electrically coupled tothe output end of the high-voltage generator through a first end of thefeedback circuit and electrically coupled to the charge pumps through aplurality of clock signal providing ends of the feedback circuitrespectively, wherein when both of the first stage switch and the secondstage switch are turned off, the high-voltage generator receives aninput signal through the input end of the high-voltage generator, andboosts the input signal through the first stage charge pump and thesecond stage charge pump, sequentially; when the first stage switch isturned on and the second stage switch is turned off, the high-voltagegenerator boosts the input signal through the second stage charge pump,and voltages across ends of the first stage switch and voltages acrossends of the second stage switch do not exceed one boost voltagedifference.
 2. The high-voltage generator of claim 1, wherein the firststage switch further comprises: a first front SPDT switch, wherein acontrol end of the first front SPDT switch is configured to receive acontrol signal, and two switch ends of the first front SPDT switch areelectrically coupled to the input end of the first stage charge pump anda ground terminal, respectively; a first inverter, wherein an input endof the first inverter is electrically coupled to a reaction end of thefirst front SPDT switch; a first back SPDT switch, wherein a control endof the first back SPDT switch is configured to receive the controlsignal, and two switch ends of the first front SPDT switch areelectrically coupled to the output end of the first stage charge pumpand an output end of the first inverter, respectively; and a firsttransistor switch comprising at least one low-voltage transistor,wherein two ends of the first transistor switch are connected inparallel with the first stage charge pump, and a control end of thefirst transistor switch is electrically coupled to a reaction end of thefirst back SPDT switch.
 3. The high-voltage generator of claim 2,wherein the second stage switch further comprises: a second front SPDTswitch, wherein a control end of the second front SPDT switch isconfigured to receive another control signal, and two switch ends of thesecond front SPDT switch are electrically coupled to the input end ofthe second stage charge pump and the ground terminal, respectively; asecond inverter, wherein an input end of the second inverter iselectrically coupled to a reaction end of the second front SPDT switch;a second back SPDT switch, wherein a control end of the second back SPDTswitch is configured to receive the another control signal, and twoswitch ends of the second front SPDT switch are electrically coupled tothe output end of the second stage charge pump and an output end of thesecond inverter, respectively; and a second transistor switch comprisingat least one low-voltage transistor, wherein two ends of the secondtransistor switch are connected in parallel with the second stage chargepump, and a control end of the second transistor switch is electricallycoupled to a reaction end of the second back SPDT switch.
 4. Thehigh-voltage generator of claim 3, wherein the low-voltage transistor,which is used in first transistor switch and the second transistorswitch, is a NMOS transistor in the low-voltage process.
 5. Thehigh-voltage generator of claim 4, wherein a corresponding SPDT switchof the first front SPDT switch, the first back SPDT switch, the secondSPDT switch and the second back SPDT switch comprises: a first couplingcapacitor, wherein one end of the first coupling capacitor iselectrically coupled to a corresponding control end of the correspondingSPDT switch; a second coupling capacitor, wherein one end of the secondcoupling capacitor is electrically coupled to the corresponding controlend of the corresponding SPDT switch; a first cross-coupled transistor,which is electrically coupled to the first coupling capacitor, thesecond coupling capacitor and a corresponding switch end of thecorresponding SPDT switch; and a second cross-coupled transistor, whichis electrically coupled to the first coupling capacitor, the secondcoupling capacitor and another corresponding switch end of thecorresponding SPDT switch.
 6. The high-voltage generator of claim 5,wherein a corresponding reaction end of the corresponding SPDT switch iselectrically coupled to another end of the second coupling capacitor. 7.The high-voltage generator of claim 5, wherein a corresponding reactionend of the corresponding SPDT switch is electrically coupled to anotherend of the first coupling capacitor.
 8. The high-voltage generator ofclaim 5, wherein the second cross-coupled transistor is respectivelyconnected in parallel with two bypass circuits, each of the bypasscircuits comprises a plurality of diodes in series.
 9. The high-voltagegenerator of claim 8, wherein the first cross-coupled transistor uses aPMOS transistor, and the second cross-coupled transistor uses a NMOStransistor.
 10. The high-voltage generator of claim 9, wherein thefeedback circuit comprises: a differential amplifier, wherein an inputend of the differential amplifier is electrically coupled to the outputend of the high-voltage generator and a reference voltage; avoltage-controlled oscillator, wherein an input end of thevoltage-controlled oscillator is electrically coupled to an output endof the differential amplifier; and a dock circuit, wherein an input endof the dock circuit is electrically coupled to an output end of thevoltage-controlled oscillator, and an output end of the dock circuit iselectrically coupled each charge pump.